For the study, published this week in the journal Scientific Reports, researchers with the Skaggs School of Pharmacy and Pharmaceutical Sciences at the University of California San Diego examined a database of more than 10 million voluntary patient records. They then narrowed the list to about 43,000 patients who solely took proton pump inhibitors (PPIs) such as Prilosec, Nexium and Prevacid.

PPIs are commonly used to treat acid reflux as well as stomach ulcers, but previous research, including a large-scale study in the British Medical Journal, found that its long-term use correlated with many adverse effects, including a 25 percent higher chance of death.

The new research, led by UC-San Diego pharmacy professor Ruben Abagyan, found that compared to a control group constricted to histamine-2 receptor anatagonists like Zantac or Pepcid, patients who took only PPIs were 28.4 times more likely to report chronic kidney disease, 4.2 times more likely to report acute kidney injury, 35.5 times more likely to report end-stage renal disease and eight times as likely to experience some unspecified kidney-related adverse reaction.

Abagyan and his colleagues also noted those who solely took PPIs were also more likely to experience “electrolyte abnormalities,” which typically occur after vomiting, diarrhea, sweating or high fever, according to the National Institutes of Health. But the abnormalities varied by individual PPIs.

Researchers acknowledge that because the database included voluntary patient reporting, the correlation frequencies “do not represent the population incidences.” And, of course, “as with any association study, causality cannot be inferred from association.”

Still, scientists hope future work will further monitor renal function and electrolytes, such as potassium, magnesium and sodium. And while histamine-2 receptor antagonists like Zantac or Pepcid haven’t been shown to be as effective as inexpensive PPIs, “they might be considered as alternatives for patients who are at high risk for developing renal and electrolytes imbalances,” researchers wrote.

Acid reflux occurs when a circular muscle (lower esophageal sphincter) joining the esophagus and stomach weakens and doesn’t effectively tighten, causing the acid from your stomach to move backward and into your esophagus, according to Mayo Clinic. This can irritate the lining of your esophagus and lead to heartburn, chest pain, difficulty swallowing, a lumpy sensation in the throat and regurgitation.